Why do we need such a big telescope? What will it look like? How will it be built? How will it handle the data?

The Square Kilometre Array Telescope (SKA) will delve further into the Universe than ever before, produce more data about the cosmos than modern-day computers can handle, and shift the focus of radio astronomy from the 'dish' to silicon.

In essence, what we are seeing is the evolution of telescopes away from the concrete and steel that forms the antennas and into the world of supercomputing, says Professor Brian Boyle, CSIRO's SKA director.

"The supercomputer is as much a part of the telescope as is the antenna.

"In the 1960s you built really big dishes to take all the data, now you put all your effort into the silicon brains behind it," Boyle says.

An array telescope is composed of lots of different antennas connected to a supercomputer via a super-fast fibre optic network.

"So in the SKA's case we're talking 3000 antennas over a minimum distance of 3000 kilometres.

"All that data is transported from the SKA at speeds of 400 terabits per second across the continent — that's about ten times greater than global internet traffic today.

"Then it's processed by a super computer capable of doing one million, million, million operations per second — about one hundred times faster than the world's fastest super computer today," says Boyle.

Scientists hope that by delving deeper into space than ever before they will be able to investigate fundamental questions about the universe, such as the evolution of galaxies, dark energy and cosmic magnetism, and probe the earliest stars and black holes.

What will the telescope look like?

Australia's bid for the telescope (see box below) will see 3000 antennas spread across Australia and New Zealand.

"The distance between the telescopes gives you the resolution the telescopes can see.

"The bigger the baseline the more fine detail you can see. So the baseline is 3000 kilometres at wavelengths we're talking about here you get to see features about 10 times better than the Hubble Space Telescope, says Boyle.

The Australasian bid covers a distance of 5000 kilometres on an east-west axis.

"East to west follows the rotation of the Earth — that allows us to do higher quality imaging over a larger area of sky," says Boyle.

The SKA will use three kinds of antennas:

Parabolic dishes around 12–15 metres in diameter, which collect data in frequencies of 1–20 gigahertz. These dishes can be rotated and will collect data on gravity, cosmic magnetism and life in the universe.

Sparse (low frequency) aperture arrays, which look a bit like TV/radio antenna, are fixed antenna that collect data in frequencies of 70–300 megahertz. They will be used to research the earliest stars to evolve in the Universe.

Dense (mid frequency) aperture arrays, which are touching dipole arrays lying on, or under, the ground. These antennas collect data in the 300 megahertz to 1 gigahertz range and will be used to study the evolution of the cosmos.

When it is finished, half the 3000 antennas will be concentrated within a 5 kilometre zone centred on the Murchison Radio Astronomy Observatory, a remote location in Western Australia. Seventy-five per cent of the antennas will be located in clumps within 180 kilometres of this central point, then another 25 stations will reach out across the continent and into New Zealand.

Building big

"The scale is so immense and the technological challenges are so immense that part of the strategy around mitigating the technical risk is to build this in stages," he says.

As time goes on the project would expand in distance and allow astronomers to see deeper into space, says Boyle.

"We will be moving into different areas of astronomy from wide field survey of astronomy to really deep field stuff," he says.

If Australia wins the bid, Boyle says the plan is to roll the first 300 antennas stretched over 100 kilometres by the end of this decade, and roll the rest out in the early part of the next decade. It is due to be fully operational by 2024.

The first stage of the project, building a telescope known as the Australian SKA Pathfinder, has already begun and will be completed regardless of whether or not Australia wins the bid for the complete telescope.

"The Australian SKA Pathfinder is a one percent scale of the SKA," says Boyle.

"It's 36 dishes stretched over six kilometres in distance. But at the same time we're putting all the infrastructure in place such as the roads and the fibre, the central control buildings, the support buildings and the power station that would at least initially help support the deployment of the full SKA," says Boyle.

The Australian SKA Pathfinder will also use a new type of radio camera, known as a phased array feed.

"Radio telescopes have essentially used a '1-pixel camera' in the past so they've got a very, very narrow area of sky that they can see," says Boyle.

"We're now moving to having a 100 pixel camera so all of a sudden we have instantaneously increased the field of view of the telescope by a factor of a hundred."

"When SKA is equipped with these technologies, because of its collecting area it will be able to look much deeper into space," he says.

Crunching data

"Today we don't have a supercomputer that will process the data from the SKA," says Boyle.

"As we build up the telescope we're building up the computer to support it.

"At the moment we have a petaflop computer — that's a thousand, million, million operations per second.

"That will be sufficient to process the data from the Australian SKA Pathfinder, but when we build the SKA we won't need a petaflop computer, we'll need an exaflop computer — a thousand times greater than its capacity," he says.

Boyle says the fastest computer today runs at 5 petaflops. But if Moore's Law, which says computer power doubles every 18 months, is correct we will have computers capable of delivering an exaflop towards the end of the decade.

"And the full SKA will be right at the leading edge of what's possible in computing technology."

Professor Brian Boyle was interviewed by Genelle Weule.

The bid

The SKA was first conceived twenty years ago when a group of scientists from a number of countries decided to build the world's largest telescope. The telescope is expected to cost around $2 billion AUD and be fully operational by 2024.

The SKA organisation has developed a number of criteria that includes:

Science and technical factors such as:- radio quietness (as the SKA will be very sensitive to radio interference it must be located in an quiet area); quality of the atmosphere (as this can can disrupt radio waves from the cosmos); climate; and geophysical characteristics.

Cost

Socioeconomic factors, political environment, security, working conditions and legal issues with each country hosting it.

A number of countries including Australia/New Zealand, Africa, Argentina/Brazil, Canada and China initially put in proposals to host the SKA, but this has now been whittled down to two contenders: Australia/New Zealand and Africa.

The Australasian proposal is spread across 5,000 kilometres on an east-west axis across Australia and New Zealand. The project is centred on the Murchison Shire in Western Australia, which is flat, dry, sparsely populated and protected for 520 kilometers in diameter against radio interference by law.

Data will be transmitted via high bandwidth fibre optic networks including the existing Australian Academic Research Network and the National Broadband Network, which runs from Geraldton to Perth. Work is underway building the Australian SKA Pathfinder, a next generation radio telescope with 36 dishes stretched over six kilometres.

The African proposal involves nine countries. It will be centred on the Karoo region in the Northern Cape of South Africa. The baseline is spread over 3,000 kilometres reaching as far north as Ghana on the north - south axis.

The Karoo region is also flat, dry, sparsely populated, and protected by law against radio interference. It already operates three radio telescopes, which according to the bid, will link the SKA into existing infrastructure such as roads, power grid and broadband backbone. Work is already underway building a telescope called MeerKat — a next generation telescope with 64 dishes.

Recommendations for the best site will be presented to a board of representatives drawn from seven countries this week.

rexw :

15 Feb 2012 8:50:40pm

I don't know that geographical stability is a determining factor at all, but I could be wrong.

However, I am much more inclined to think that it will be the skills of the Professors in Perth that would make the pendulum swing our way. Few would be able to equal the scientific skills of the likes of Peter Quinn from UWA and only people like that can make this a real success. A once in a lifetime project, unique in the world.

Kevin Barraclough :

15 Feb 2012 11:19:53pm

Dear Sir/Maam, As to which choice to make, leave us with only one conclusion. Two stable countries- Australia and New Zealand, against nine different nations that may be ravaged by political strife, civil war or unrest from poverty or multi national takeovers.This I am sure is obvious to all of you. An international effort invested in the Southern Islands for the benefit of all Mankind into the future. As in all aspects of our great venture into the heavens, this HAS to be our way forward from now on. It is simply impossible for one country to do it on their own. Mankind in a united effort, working together for the benefit of The Human Race.

Todd :

15 Feb 2012 6:00:56pm

I really hope we get this. Im so glad that in these times of arguing politicians and the economic crisis, that we still find the time and money to help us answer the biggest questions we can ever ask. Almost brings a tear to my eye.

jimb :

15 Feb 2012 6:39:49pm

Good to see Australia supporting some big science.We have always had a good reputation in Astronomy and Radio Astronomy. It is good to see the government backing up the science community on this big endeavour.

Joel from Florida :

Emil Kane :

16 Feb 2012 7:33:48pm

That is a noble thought. Unfortunately South Africa and New Zealand are about 150 degrees apart in longitude, which means that their antennas could not look at the same part of the sky at the same time, an essential requirement for radio astronomy.

Titus :

16 Feb 2012 1:37:56pm

Apart from discussd geopolitical aspects, and the East/West alignment, I had thought there were a host of minor issues for the African bid that might seem minor, but be as detrimental as the bird dropping that held up the operations of the LHC in 2009.

1/ Wild Animals - Can't see a Kangaroo or dingo having much luck disturbing a dish, but put a herd of elephants against it....

2/ Local Scavengers - When you can get a decent bit of money for scrap metal, whats to stop the poor locals in some country from pulling a far flung antennae apart for the copper and other metals inside?

3/ Power - Apart from the electicity infrastructure facing the same threat as the antennae as above, the African bid will need to ensure that grid providing power is stable, reliable and ideally green - which might seem a bit over the top when the local populace don't have basic services themselves

4/ Inequity - Say Australia has to stump up half the cost, about $1 billion: its pocket change really. For Africa to have to pay a similar amount, when they have enought trouble with providing basic services (as above) really is too much. And where would the money come from? loans from the World Bank which they will never pay back? Funding from a superpower looking to buy influence? Cuts to hospitals and schools?

I guess there are just to many 'unknown unknowns' that the African bid will need to safeguard against that really should put the ball in Australia's court.

(on the flipside for the Aussie bid - I hope that those dishes are cyclone proof....)

Scientistsmurf :

17 Feb 2012 8:52:25am

I certainly agree 2 billion is small change and would be better spent in Australia. Why don't we ask all those nice multi-national companies currently ripping resources out of Australia to chip in 1% of their profits? Then we could go ahead and build the SKA anyway.

andremu :

Ivan :

22 Feb 2012 11:21:12am

Your comments are spot on Titus. Gaurds against poaching are only partly sussessfull and come at huge expense by diverting funds from the provision of desperately needed services to the people of those countries. Currently in S. Africa cast iron manhole covers in the streets and on verges are stolen and sold as scrap metal leaving pit traps for people to fall into.